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How to resize a photo to exact pixel dimensions for upload
Short answer
- If the aspect ratio is different, crop first and resize second. With Keep aspect ratio off, entering both dimensions on a photo with a different ratio stretches or squashes it.
- Without a stated requirement, 1,000–2,000 pixels wide is usually plenty for a photo viewed on screen.
- Enlarging a small photo does not make it sharper. Always keep the original.
Resolution, aspect ratio and file size are different things
| Term | Meaning | Tool that changes it |
|---|---|---|
| Resolution (pixel size) | Width × height in pixels, e.g. 1200 × 900 | Resize Image |
| Aspect ratio | The shape: width to height, e.g. 4:3 or 1:1 | Crop Image |
| File size | How much space the file takes, in KB or MB | Compress Image |
If an upload page says “1000 × 1000 px”, it is asking for a resolution and a square 1:1 shape at the same time; “under 500 KB” is a file-size rule. Keeping the three apart tells you which tool to use, in which order.
What different uploads need
- Online shop product photos: many marketplaces recommend square (1:1) images. Follow the pixel and file-size figures in the platform’s seller help pages.
- Blog and forum posts: most sites scale images to the width of the page, so there is no need to upload a full-size phone original, which is often 4,000 pixels wide or more. Around 1,000–2,000 pixels wide uploads faster and stays under size limits.
- ID and passport photos for applications: the form usually states exact pixels and a size limit. To convert millimetre sizes to pixels, see passport photo size in pixels.
Steps
- Match the shape: if the original and the target ratio differ, choose a preset in Crop Image (Free, 1:1, 4:3, 3:2 or 16:9) and move the frame over the part to keep. Under Precision settings you can also set the X and Y position, width and height in percent.
- Set the pixel size: in Resize Image, leave Keep aspect ratio on and enter only the width or the height; the other is calculated from the original. A 4000 × 3000 photo resized to a width of 1200 becomes 1200 × 900.
- Check the output format: Resize Image saves JPG by default. If it is a PNG with a transparent background, switch the output to PNG; JPG turns transparent areas white.
- Several images: each image has its own settings. Use Apply current settings to all images only when they all need the same size; applying one exact width and height to photos of different shapes will stretch some of them.
- Meet the file-size limit: if there is still a KB or MB limit, finish with a target size in Compress Image.
Watch out for
- With Keep aspect ratio off, entering both width and height distorts faces and text whenever the shape does not match. If you need two exact dimensions, crop to the right ratio first.
- Fewer pixels does not always mean a much smaller file; the format and quality setting matter too.
- Cropping discards the area outside the frame. Check the downloaded file to make sure no edge of the product or text was cut off.
- The image tools accept up to 30 images at a time, each up to 40 MB and 32 megapixels; very large images or many files may be limited further by your device’s memory.
Checking the result
Check the width and height in the file’s properties (on Windows, right-click > Properties > Details; on a Mac, Get Info) and view it at full size to judge sharpness. If it looks soft after uploading, the site may have resized it again; try making it at the site’s recommended size.